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June 1998
Mood during epidural patient-controlled analgesia with morphine or fentanyl.
Tsueda K, Mosca PJ, Heine MF, Loyd GE, Durkis DAE, Malkani AL, Hurst HE. Anesthesiology 1998;88:885-91.
[ see abstract below ]
It is always a pleasant surprise to come across systematic documentation and explanation of one's long-held clinical biases! Our usual practice for postoperative pain management in infants and children who have had lumbar or caudal epidural catheters placed in the operating room is to run infusions of bupivacaine and either morphine or fentanyl. The choice between the two opioids is generally based on the preference of the operating room anesthesiologist, and is in some cases related to that person's guess as to the placement of the catheter tip. As we are reluctant to place thoracic epidural catheters in anesthetized patients (most of our population), we are often left to hope that a catheter "threaded up" to the appropriate level has actually arrived at its intended destination. Many of my colleagues who have demonstrated a good local anesthetic block would order fentanyl, adding morphine to the infusion in those instances where the block was less clearly defined. Having providing postoperative pain management for these patients for several years, I feel that, as a group, the morphine patients generally appear more comfortable.
Kentaro Tsueda and colleagues at the University of Louisville have done a thorough investigation of the relationship between mood and epidurally administered opioids. They randomized 52 healthy adults to receive patient-controlled epidural analgesia (PCEA) with equi-analgesic doses of either morphine or fentanyl, and subsequently measured pain (VAS), opioid side-effects (respiratory depression, somnolence, pruritus, nausea and vomiting, hallucinations and ileus), and plasma drug concentrations.
The primary outcome measure was "the bipolar form of the Profile of Mood States" on which patients rated each of 6 mood states along a continuum (composed-anxious, agreeable-hostile, elated-depressed, confident-unsure, energetic-tired, and clearheaded-confused). These measurements were made during the 48 hours that the PCEA was running and 24 hours after its termination. Clear differences between the effects of the two drugs on almost all aspects of mood were demonstrable. The differences increased with time, and were measurable for 24 hours after discontinuation of PCEA. Patients receiving epidural morphine reported progressive improvements in mood, while those treated with epidural fentanyl became more anxious, hostile, depressed, unsure, tired, and confused. Of particular interest was the lack of association between mood and pain or other kinds of discomfort. The authors explain their findings on the basis of the CSF pharmacokinetics of each drug. As a result of its hydrophilicity, morphine accumulates in the epidural space and CSF, and tends to spread rostrally over time. In contrast, CSF fentanyl concentrations decline after administration and rapidly equilibrate with plasma concentrations. Low plasma fentanyl concentrations, in the range of those measured in this study,have been associated with negative emotional states. I now have another argument in favor of morphine, and rounds certainly are more fun when the patients are in a good mood.
Return to the Current Literature Review Front Page, or read the abstract:
ABSTRACT
BACKGROUND: Mood states during epidural opioids are not known. The authors studied the change in mood during the 48-h period of epidural morphine and epidural fentanyl in 47 patients after elective hip or knee joint arthroscopy.
METHODS: An epidural catheter was inserted at the L2-L3 or L3-L4 interspace. Anesthesia was induced with thiopenthal and maintained with isoflurane and nitrous oxide. One hour before the conclusion of the operation, patients received an epidural bolus injection of 2 mg morphine (n = 25) or 100 �g fentanyl (n = 24), followed by the same opiate (125 µg/ml morphine or 25 µg/ml fentanyl) epidurally delivered by a patient-controlled analgesia (PCA) pump in the postoperative period for 48 h. Mood was assessed using the bipolar form of the Profile of Mood States before operation and 24 h, 48 h, and 72 h after operation.
RESULTS: There was no significant difference in pain intensity between the groups during epidural PCA. Mood states became more positive over time in the patients who received morphine (P < 0.01 at 48 h) and negative in those who were given fentanyl (P < 0.01 at 24 and 48 h, respectively) compared with those before the operation, and they were more positive in the morphine than in the fentanyl group at 24 h, 48 h (P < 0.05), and 72 h (P < 0.01). Patients in the morphine group were more composed, agreeable, elated, confident, energetic, and clearheaded than were those in the fentanyl group (P < 0.05). There was no correlation between mood scores and pain scores in either group. There was an inverse correlation at 48 h between mood scores and plasma fentanyl concentrations (r = -0.58, P = 0.05).
CONCLUSION: Mood states are significantly more positive during epidural morphine PCA than they are during epidural fentanyl PCA.
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